Mechanical pencil



July 16, 1963- F. J. STOEBERL MECHANICAL PENCIL Filed July 7. 1960United States Patent 3,097,628 MECHANICAL PENCIL Frank J. Stoeberl,Chicago, Ill., assignor to Dur-O-Lite Pencil Company, Melrose Park,Ill., .a corporation of Delaware Filed July 7, 1960, Sax-.No. 41,372 2Claims. (Cl. 120-18) The invention relates to pencils and has referencein particular to a mechanical pencil, the body portion of which isformed of wood and wherein the tapering tip and the mechanical means forpropelling the lead 131B formed of metal.

Wood pencils of the mechanical type are relatively cheap to manufactureand they are preferred by many due in part to the economy in their use,the :fact that they are longer than the conventional mechanical penciland also because they are relatively light in weight. However, certainfactors which arise in the course of their manufacture have resulted inan unsatisfactory product. One of these manufacturing problems concernsthe metal tip and its effective attachment to the formed lower end ofthe wood body portion. In this respect the improvements of the inventionattain two desirable advantages. The tip is formed irom a metal blank sothat the desired economy in manufacturing is still obtained and thesplit metal tip thus formed is snapped onto the preformed end ofthe-wood pencil and the same is maintained in attached relation by'theinherent resiliency of the metal tip.

Other advantages and objectives of the invention are to provide a woodpencil of the non-magazine type having one length of lead propelled bymechanical means so that the pencil can be discarded when the lead iscompletely used; to provide a mechanical pencil which will simulate thecommon wood lead pencil in length, weight and appearance; and to providea wood pencil as described wherein the metal tip is frictionally heldwhile permitting rotation thereof for actuating the propelling means forthe lead.

Another object of the invention is the provide a metal tip for the woodbody portion of a mechanical pencil which is operatively held on thepreformed end of the wood body portion by the resiliency of the tip andwhich also functions to apply a frictional gripping action to the leadadjacent the point protruding from the said tip.

With these and various other objects in view, the invention may consistof certain novel features of construction and operation, as will be morefully described and particularly pointed out in the specification,drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the device and whereinlike reference characters are used to designate like parts- FIGURE 1 isan elevational view of the wood pencil of the invention showing themetal tip in position to be attached thereto;

FIGURE 2 is a vertical sectional view taken substantially through thecenter of the pencil and illustrating the constructional features of thelead propelling mechanism and the metal tip;

FIGURE 3 is a transverse sectional view taken on line 33 of FIGURE 2;

FIGURE 4 is a transverse sectional view taken along line 4-4 of FIGURE2;

FIGURE 5 is a transverse sectional view taken along line 55 of FIGURE 2;and

FIGURE 6 is a view showing the metal blank from which the tip is formed.

In the drawings the invention is illustrated in connection with anon-magazine type of pencil 10 having a ice body portion 11 formediofwood, although other material such as hard rubber, plastic and fiber maybe used. The body portion 11 is provided with a central bore 12extending axially tor the length or the body portion. A lateral groove13 extends along one side of the central bore and communicates therewithfor its entire length. The upper end of the wood body portion isprovided with the usual eraser 14 and the lower end is formed at 15 intothe tapering shape as shown in FIGURE 1. The said shape provides thetapering end 16, the annular groove 17, and the cylindrical portion 18which issomewhat reduced in diameter as compared to that of the bodyportion 11.

The size of ,tip 20 in regards to its diameter, length and taper is notparticularly critical to the invention, since the tip is expandablebeing formed from the blank 21 as shown in FIGURE '6. The material ofthe blank may be metal, plastic or other material having someresiliency. Therefore, in accordance with the invention the tip hasinherent resiliency in a transverse direction which permits the tip toexpand circumferentially. Normal variations in the wood or othermaterial of the body portion will produce wide variations in thediameter of the taper 15 irrespective of the forming operation that maybe employed in producing the taper. Therefore, were it not for theresiliency which is built into the metal tip 20, the end 15 would haveto be formed to exact dimensions, within one or two thousandths of aninch, to properly fit within a conical tip such as may be formed a tubeand which in turn would thus have exact dimensions.

The ability of the present tip to expand in a transverse directionwhereby to enlarge its diameter is additionally employed to frictionallygrip the lead 22 adject the point which protrudes from the metal tip. Byfrictionally gripping the protruding point of the lead, the same is heldin place within the pencil and is prevented from inadvertently droppingout when the pencil is held vertically. The said lead is propelled bymechanism best shown in FIGURE 2 and which will now be described.

The said propelling mechanism for the lead 22 is of the conventionaltype consisting essentially of the spiral member 24 located within andextending for the entire length of the central bore 12. By means of thepunches 25 the spiral member at its extreme lower end is secured to thetip 20 at the intermediate cylindrical portions 26 of the tip. The leadis disposed axially of the spiral member and the same protrudes from theend 27 of the tip. The plunger 28 functions to propel the lead, since itis provided with a hook 30 at its upper end and which rides within thelateral groove 13. Accordingly, rotation of the tip to rotate the spiralmember in the proper direction will cause the plunger to move down andpropel the lead.

As previously described the metal tip 20 is stamped from the blank 21.The top cylindrical end of the formed metal tip is provided with one ormore detents 32 and these are aligned with and ride within the groove 17to thus retain the metal tip in rotative relation on the tapered end ofthe wood pencil. It is preferred that the diameter of the cylindricalportion 18 of the wood pencil be slightly larger than the metal tipfollowing formation of the same and wherein the edges forming the slot3-3 will be in substantial contact. This is desirable since the tipshould be snapped into place on the tapered end 15. With the metal tipthus in place the top part containing the detents 32 will be expanded toa slight extent and thus the expansibility of the metal tip functions tohold and retain the tip on the said tapered end. Of course, the detents32, since they ride in the groove 17, also assist in this function ofholding the metal tip in place, and additionally the detents provide forrotation of the tip for rotating the spiral member in order to propelthe lead from the pencil. Although the desired expansion of the metaltip may open the slit 33 in the top part thereof, this does notmaterially effect the extreme lower end of the tip so that this endfunctions effectively to frictionally grip the protruding lead point.Since the pencil is of wood it naturally follows that the taper 15 issubjected to considerable wear. However, the resiliency of the tip 20will take up any wear and thus the tip is held to the wood pencil forthe entire life of the article.

The invention is not to be limited to or by details of construction ofthe particular embodiment thereof illustrated by the drawings, asvarious other forms of the device will, of course, be apparent to thoseskilled in the art Without departing from the spirit of the invention orthe scope of the claims.

What is claimed is:

1. ha mechanical pencil, a body portion having an approximately centrallongitudinally extending bore, said body portion having a section of itslength at its lower terminal end reduced in diameter, a circumferentialgroove formed in the section of reduced diameter, a circumferentiallyexpandable sheet metal tip in telescoped relation on the exterior of thesection of reduced diameter, said metal tip having a tapering formationin the direction of its length and having a slit extendinglongitudinally from end to end, at least one detent formed in the metaltip adjacent its top end and which has interfitting relation with thecircumferential groove, whereby the metal tip is resiliently retained onthe section of reduced diameter by the expandability of the metal tipwhile permitting relative rotation of the metal tip, means forpropelling a length of lead through the metal tip to cause the lead toproject from the tapered end of the metal tip, said lead propellingmeans at one end having a location within the metal tip and being fixedthereto, and said lead propelling means having its other end extendinginto the longitudinal bore of the said body portion.

2. In a mechanical pencil, a body portion having an approximatelycentral longitudinally extending bore, a circumferential groove formedin the body portion adjacent one terminal end thereof, acircumferentially expandable metal tip in telescoped relation on thesaid terminal end of the body portion, said metal tip consisting ofsheet metal substantially uniform in thickness and being characterizedby a slit extending longitudinally from end to end, said tip having acylindrical portion at one end and a tapering portion at its other end,at least one detent formed in the cylindrical portion of the metal tipand which rides within the circumferential groove to assist inresiliently maintaining the tip on the said terminal end of the bodyportion while permitting rotation of the tip, means for propelling alength of lead through the metal tip to cause the same to project fromthe tapered end of the tip, said lead propelling means at one end havinga location within the metal tip and being fixed to the tapered end ofthe same, and said lead propelling means having its other end extendinginto the longitudinal bore of the said body portion, said metal tip atits tapered end also having resilient contact with the projecting end ofthe length of lead by reason of its expandability.

References Cited in the file of this patent UNITED STATES PATENTS527,803 McCollum Oct. 23, 1894 1,410,666 Fisher Mar. 28, 1922 1,997,424Lynn Apr. 9, 1935

1. IN A MECHANICAL PENCIL, A BODY PORTION HAVING AN APPROXIMATELYCENTRAL LONGITUDINALLY EXTENDING BORE, SAID BODY PORTION HAVING ASECTION OF ITS LENGTH AT ITS LOWER TERMINAL END REDUCED IN DIAMETER, ACIRCUMFERENTIAL GROOVE FORMED IN THE SECTION OF REDUCED DIAMETER, ACIRCUMFERENTIALLY EXPANDABLE SHEET METAL TIP IN TELESCOPED RELATION ONTHE EXTERIOR OF THE SECTION OF REDUCED DIAMETER, SAID METAL TIP HAVING ATAPERING FORMATION IN THE DIRECTION OF ITS LENGTH AND HAVING A SLITEXTENDING A LONGITUDINALLY FROM END TO END, AT LEST ONE DETENT FORMED INTHE METAL TIP ADJACENT ITS TOP END AND WHICH HAS INTERFITTING RELATIONWITH THE CIRCUMFERENTIAL GROOVE, WHEREBY THE METAL TIP IS RESILIENTLYRETAINED ON THE SECTION OF REDUCED DIAMETER BY THE EXPANDABILITY OF THEMETAL TIP WHILE PERMITTING RELATIVE ROTATION OF THE METAL TIP, MEANS FORPROPELLING A LENGTH OF LEAD THROUGH THE METAL TIP TO CAUSE THE LEAD TOPROJECT FROM THE TAPERED END OF THE METAL TIP, SAID LEAD PROPELLINGMEANS AT ONE END HAVING A LOCATION WITHIN THE METAL TIP AND BEING FIXEDTHERETO, AND SAID LEAD PROPELLING MEANS HAVING ITS OTHER END EXTENDINGINTO THE LONGITUDINAL BORE OF THE SAID BODY PORTION.